This application generally relates to resistive random access memory, which can be referred to as RRAM or ReRAM.
RRAM cells can include a select transistor and a programmable resistor. Current can flow through the programmable resistor responsive to a word line voltage VWL applied to the gate of the select transistor and a bit line voltage VBL applied to the source of the select transistor. Responsive to the current, the programmable resistor can change between a relatively high resistance and a relatively low resistance, which can be referred to as a “SET” operation; or between the relatively low resistance and the relatively high resistance, which can be referred to as a “RESET” operation. However, it can be difficult to accurately characterize the resistance of the programmable resistor, that is, to accurately detect write operations such as SET or RESET in an RRAM cell. Additionally, it can be undesirable for the current to exceed a certain value, which can cause the resistance of the programmable resistor to drop below the relatively low resistance. Such a condition can be referred to as “over-SET.”